Calculating Roof Materials: Satellite Roofing Report

Contractors please help me:

I have a roofing report from KRL Inc. They taut their reports as up to 96% accurate. What is your experience with KRL or other companies such as these offering such reports?

Do squares of asphalt shingles need to be added to the report area squares for ridge caps?

If so, the report gives lengths for ridges allowing calculation. How is the calculation done? (I an cutting 3-tab shingles for ridge cap covering.)

Is material quantity for covering a ridge vent the same as a ridge cap?

How would starter row material be calculated? (I assume using eve and rake lengths and ??)

Do you have a rule of thumb for calculating nail usage per square of area for attaching under-layment felt and shingles? For attaching drip edge? Etc.?

Is 5% waste a reasonable number for asphalt shingles?

Thank you for your help.
Ed Haney

The roof report typically is the roof area and not a calculation for materials. Depending on your roof complexity, add 7.5% for waste as a reasonably accurate estimate and then starter and cap separately. Depends on the type of roof and complexity. Figure 30 LF per bundle for Cap and 110 per bundle for starter (these are if you plan to use specialty cap and starter). Use 26 feet per bundle for cap, if you’re cutting 3 tabs, and 78 feet per bundle for starter. Not sure why you would do that but not your question. Starter is perimeter, eaves plus rakes.

Ridge vent comes in 4 foot pieces. I forget the exact calculation for 1 1/4" nails but I see to remember it was around 1 box per every 14 squares, give or take a little. That’s if you 6 nail. If you only 4 nail, it would be around 20 sq per box. We use plastic cap for felt and I think you get slightly more coverage per box than roofing nails for shingles per square.

I would think all that will get you close enough. If you need it 100% exact, send me your roof report and I could run it fairly easy. My numbers/calculation are in a workbook, I just plug the roof parameters in and it spits out the right numbers for materials using Excel formulas.


Thank you for your helpful reply. I really do appreciate it.

I will send you my roof report so I can see how my rough material calculations compare to a Pro’s (your calcs.)

Thanks again,